diff options
author | Daniel Veillard <veillard@src.gnome.org> | 2006-06-06 13:27:03 +0000 |
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committer | Daniel Veillard <veillard@src.gnome.org> | 2006-06-06 13:27:03 +0000 |
commit | 69839ba1974ba8a7e996652bb2f7865de33b366f (patch) | |
tree | 8a397b96e9dada77ba6d1378dfbddfa317536e26 /doc/entities.html | |
parent | 080152c9017a0ee4b97149d54f85fea3ab348b6d (diff) | |
download | libxml2-69839ba1974ba8a7e996652bb2f7865de33b366f.tar.gz |
preparing release of 2.6.25 Daniel
* configure.ini NEWS doc//* libxml.spec.in : preparing release of 2.6.25
Daniel
Diffstat (limited to 'doc/entities.html')
-rw-r--r-- | doc/entities.html | 73 |
1 files changed, 37 insertions, 36 deletions
diff --git a/doc/entities.html b/doc/entities.html index c234b41e..413dccef 100644 --- a/doc/entities.html +++ b/doc/entities.html @@ -7,34 +7,35 @@ H1 {font-family: Verdana,Arial,Helvetica} H2 {font-family: Verdana,Arial,Helvetica} H3 {font-family: Verdana,Arial,Helvetica} A:link, A:visited, A:active { text-decoration: underline } -</style><title>Entities or no entities</title></head><body bgcolor="#8b7765" text="#000000" link="#a06060" vlink="#000000"><table border="0" width="100%" cellpadding="5" cellspacing="0" align="center"><tr><td width="120"><a href="http://swpat.ffii.org/"><img src="epatents.png" alt="Action against software patents" /></a></td><td width="180"><a href="http://www.gnome.org/"><img src="gnome2.png" alt="Gnome2 Logo" /></a><a href="http://www.w3.org/Status"><img src="w3c.png" alt="W3C Logo" /></a><a href="http://www.redhat.com/"><img src="redhat.gif" alt="Red Hat Logo" /></a><div align="left"><a href="http://xmlsoft.org/"><img src="Libxml2-Logo-180x168.gif" alt="Made with Libxml2 Logo" /></a></div></td><td><table border="0" width="90%" cellpadding="2" cellspacing="0" align="center" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3" bgcolor="#fffacd"><tr><td align="center"><h1>The XML C parser and toolkit of Gnome</h1><h2>Entities or no entities</h2></td></tr></table></td></tr></table></td></tr></table><table border="0" cellpadding="4" cellspacing="0" width="100%" align="center"><tr><td bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td valign="top" width="200" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Developer Menu</b></center></td></tr><tr><td bgcolor="#fffacd"><form action="search.php" enctype="application/x-www-form-urlencoded" method="get"><input name="query" type="text" size="20" value="" /><input name="submit" type="submit" value="Search ..." /></form><ul><li><a href="index.html" style="font-weight:bold">Main Menu</a></li><li><a href="html/index.html" style="font-weight:bold">Reference Manual</a></li><li><a href="examples/index.html" style="font-weight:bold">Code Examples</a></li><li><a href="guidelines.html">XML Guidelines</a></li><li><a href="tutorial/index.html">Tutorial</a></li><li><a href="xmlreader.html">The Reader Interface</a></li><li><a href="ChangeLog.html">ChangeLog</a></li><li><a href="XSLT.html">XSLT</a></li><li><a href="python.html">Python and bindings</a></li><li><a href="architecture.html">libxml2 architecture</a></li><li><a href="tree.html">The tree output</a></li><li><a href="interface.html">The SAX interface</a></li><li><a href="xmlmem.html">Memory Management</a></li><li><a href="xmlio.html">I/O Interfaces</a></li><li><a href="library.html">The parser interfaces</a></li><li><a href="entities.html">Entities or no entities</a></li><li><a href="namespaces.html">Namespaces</a></li><li><a href="upgrade.html">Upgrading 1.x code</a></li><li><a href="threads.html">Thread safety</a></li><li><a href="DOM.html">DOM Principles</a></li><li><a href="example.html">A real example</a></li><li><a href="xml.html">flat page</a>, <a href="site.xsl">stylesheet</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>API Indexes</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="APIchunk0.html">Alphabetic</a></li><li><a href="APIconstructors.html">Constructors</a></li><li><a href="APIfunctions.html">Functions/Types</a></li><li><a href="APIfiles.html">Modules</a></li><li><a href="APIsymbols.html">Symbols</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Related links</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="http://mail.gnome.org/archives/xml/">Mail archive</a></li><li><a href="http://xmlsoft.org/XSLT/">XSLT libxslt</a></li><li><a href="http://phd.cs.unibo.it/gdome2/">DOM gdome2</a></li><li><a href="http://www.aleksey.com/xmlsec/">XML-DSig xmlsec</a></li><li><a href="ftp://xmlsoft.org/">FTP</a></li><li><a href="http://www.zlatkovic.com/projects/libxml/">Windows binaries</a></li><li><a href="http://www.blastwave.org/packages.php/libxml2">Solaris binaries</a></li><li><a href="http://www.explain.com.au/oss/libxml2xslt.html">MacOsX binaries</a></li><li><a href="http://libxmlplusplus.sourceforge.net/">C++ bindings</a></li><li><a href="http://www.zend.com/php5/articles/php5-xmlphp.php#Heading4">PHP bindings</a></li><li><a href="http://sourceforge.net/projects/libxml2-pas/">Pascal bindings</a></li><li><a href="http://libxml.rubyforge.org/">Ruby bindings</a></li><li><a href="http://tclxml.sourceforge.net/">Tcl bindings</a></li><li><a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Bug Tracker</a></li></ul></td></tr></table></td></tr></table></td><td valign="top" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%"><tr><td><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table border="0" cellpadding="3" cellspacing="1" width="100%"><tr><td bgcolor="#fffacd"><p>Entities in principle are similar to simple C macros. An entity defines an -abbreviation for a given string that you can reuse many times throughout the -content of your document. Entities are especially useful when a given string -may occur frequently within a document, or to confine the change needed to a -document to a restricted area in the internal subset of the document (at the -beginning). Example:</p><pre>1 <?xml version="1.0"?> +</style><title>Entities or no entities</title></head><body bgcolor="#8b7765" text="#000000" link="#a06060" vlink="#000000"><table border="0" width="100%" cellpadding="5" cellspacing="0" align="center"><tr><td width="120"><a href="http://swpat.ffii.org/"><img src="epatents.png" alt="Action against software patents" /></a></td><td width="180"><a href="http://www.gnome.org/"><img src="gnome2.png" alt="Gnome2 Logo" /></a><a href="http://www.w3.org/Status"><img src="w3c.png" alt="W3C Logo" /></a><a href="http://www.redhat.com/"><img src="redhat.gif" alt="Red Hat Logo" /></a><div align="left"><a href="http://xmlsoft.org/"><img src="Libxml2-Logo-180x168.gif" alt="Made with Libxml2 Logo" /></a></div></td><td><table border="0" width="90%" cellpadding="2" cellspacing="0" align="center" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3" bgcolor="#fffacd"><tr><td align="center"><h1>The XML C parser and toolkit of Gnome</h1><h2>Entities or no entities</h2></td></tr></table></td></tr></table></td></tr></table><table border="0" cellpadding="4" cellspacing="0" width="100%" align="center"><tr><td bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td valign="top" width="200" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Developer Menu</b></center></td></tr><tr><td bgcolor="#fffacd"><form action="search.php" enctype="application/x-www-form-urlencoded" method="get"><input name="query" type="text" size="20" value="" /><input name="submit" type="submit" value="Search ..." /></form><ul><li><a href="index.html" style="font-weight:bold">Main Menu</a></li><li><a href="html/index.html" style="font-weight:bold">Reference Manual</a></li><li><a href="examples/index.html" style="font-weight:bold">Code Examples</a></li><li><a href="guidelines.html">XML Guidelines</a></li><li><a href="tutorial/index.html">Tutorial</a></li><li><a href="xmlreader.html">The Reader Interface</a></li><li><a href="ChangeLog.html">ChangeLog</a></li><li><a href="XSLT.html">XSLT</a></li><li><a href="python.html">Python and bindings</a></li><li><a href="architecture.html">libxml2 architecture</a></li><li><a href="tree.html">The tree output</a></li><li><a href="interface.html">The SAX interface</a></li><li><a href="xmlmem.html">Memory Management</a></li><li><a href="xmlio.html">I/O Interfaces</a></li><li><a href="library.html">The parser interfaces</a></li><li><a href="entities.html">Entities or no entities</a></li><li><a href="namespaces.html">Namespaces</a></li><li><a href="upgrade.html">Upgrading 1.x code</a></li><li><a href="threads.html">Thread safety</a></li><li><a href="DOM.html">DOM Principles</a></li><li><a href="example.html">A real example</a></li><li><a href="xml.html">flat page</a>, <a href="site.xsl">stylesheet</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>API Indexes</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="APIchunk0.html">Alphabetic</a></li><li><a href="APIconstructors.html">Constructors</a></li><li><a href="APIfunctions.html">Functions/Types</a></li><li><a href="APIfiles.html">Modules</a></li><li><a href="APIsymbols.html">Symbols</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Related links</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="http://mail.gnome.org/archives/xml/">Mail archive</a></li><li><a href="http://xmlsoft.org/XSLT/">XSLT libxslt</a></li><li><a href="http://phd.cs.unibo.it/gdome2/">DOM gdome2</a></li><li><a href="http://www.aleksey.com/xmlsec/">XML-DSig xmlsec</a></li><li><a href="ftp://xmlsoft.org/">FTP</a></li><li><a href="http://www.zlatkovic.com/projects/libxml/">Windows binaries</a></li><li><a href="http://www.blastwave.org/packages.php/libxml2">Solaris binaries</a></li><li><a href="http://www.explain.com.au/oss/libxml2xslt.html">MacOsX binaries</a></li><li><a href="http://libxmlplusplus.sourceforge.net/">C++ bindings</a></li><li><a href="http://www.zend.com/php5/articles/php5-xmlphp.php#Heading4">PHP bindings</a></li><li><a href="http://sourceforge.net/projects/libxml2-pas/">Pascal bindings</a></li><li><a href="http://libxml.rubyforge.org/">Ruby bindings</a></li><li><a href="http://tclxml.sourceforge.net/">Tcl bindings</a></li><li><a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Bug Tracker</a></li></ul></td></tr></table></td></tr></table></td><td valign="top" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%"><tr><td><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table border="0" cellpadding="3" cellspacing="1" width="100%"><tr><td bgcolor="#fffacd"><p>Entities in principle are similar to simple C macros. An entity defines +anabbreviation for a given string that you can reuse many times throughout +thecontent of your document. Entities are especially useful when a given +stringmay occur frequently within a document, or to confine the change needed +to adocument to a restricted area in the internal subset of the document (at +thebeginning). Example:</p><pre>1 <?xml version="1.0"?> 2 <!DOCTYPE EXAMPLE SYSTEM "example.dtd" [ 3 <!ENTITY xml "Extensible Markup Language"> 4 ]> 5 <EXAMPLE> 6 &xml; -7 </EXAMPLE></pre><p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing -its name with '&' and following it by ';' without any spaces added. There -are 5 predefined entities in libxml2 allowing you to escape characters with -predefined meaning in some parts of the xml document content: -<strong>&lt;</strong> for the character '<', <strong>&gt;</strong> -for the character '>', <strong>&apos;</strong> for the character ''', -<strong>&quot;</strong> for the character '"', and -<strong>&amp;</strong> for the character '&'.</p><p>One of the problems related to entities is that you may want the parser to -substitute an entity's content so that you can see the replacement text in -your application. Or you may prefer to keep entity references as such in the -content to be able to save the document back without losing this usually -precious information (if the user went through the pain of explicitly -defining entities, he may have a a rather negative attitude if you blindly -substitute them as saving time). The <a href="html/libxml-parser.html#xmlSubstituteEntitiesDefault">xmlSubstituteEntitiesDefault()</a> -function allows you to check and change the behaviour, which is to not -substitute entities by default.</p><p>Here is the DOM tree built by libxml2 for the previous document in the -default case:</p><pre>/gnome/src/gnome-xml -> ./xmllint --debug test/ent1 +7 </EXAMPLE></pre><p>Line 3 declares the xml entity. Line 6 uses the xml entity, by +prefixingits name with '&' and following it by ';' without any spaces +added. Thereare 5 predefined entities in libxml2 allowing you to escape +characters withpredefined meaning in some parts of the xml document +content:<strong>&lt;</strong>for the character '<', +<strong>&gt;</strong>for the character '>', +<strong>&apos;</strong>for the character +''',<strong>&quot;</strong>for the character '"', +and<strong>&amp;</strong>for the character '&'.</p><p>One of the problems related to entities is that you may want the parser +tosubstitute an entity's content so that you can see the replacement text +inyour application. Or you may prefer to keep entity references as such in +thecontent to be able to save the document back without losing this +usuallyprecious information (if the user went through the pain of +explicitlydefining entities, he may have a a rather negative attitude if you +blindlysubstitute them as saving time). The <a href="html/libxml-parser.html#xmlSubstituteEntitiesDefault">xmlSubstituteEntitiesDefault()</a>function +allows you to check and change the behaviour, which is to notsubstitute +entities by default.</p><p>Here is the DOM tree built by libxml2 for the previous document in +thedefault case:</p><pre>/gnome/src/gnome-xml -> ./xmllint --debug test/ent1 DOCUMENT version=1.0 ELEMENT EXAMPLE @@ -49,16 +50,16 @@ DOCUMENT version=1.0 ELEMENT EXAMPLE TEXT - content= Extensible Markup Language</pre><p>So, entities or no entities? Basically, it depends on your use case. I -suggest that you keep the non-substituting default behaviour and avoid using -entities in your XML document or data if you are not willing to handle the -entity references elements in the DOM tree.</p><p>Note that at save time libxml2 enforces the conversion of the predefined -entities where necessary to prevent well-formedness problems, and will also -transparently replace those with chars (i.e. it will not generate entity -reference elements in the DOM tree or call the reference() SAX callback when -finding them in the input).</p><p><span style="background-color: #FF0000">WARNING</span>: handling entities -on top of the libxml2 SAX interface is difficult!!! If you plan to use -non-predefined entities in your documents, then the learning curve to handle -then using the SAX API may be long. If you plan to use complex documents, I -strongly suggest you consider using the DOM interface instead and let libxml -deal with the complexity rather than trying to do it yourself.</p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html> + content= Extensible Markup Language</pre><p>So, entities or no entities? Basically, it depends on your use case. +Isuggest that you keep the non-substituting default behaviour and avoid +usingentities in your XML document or data if you are not willing to handle +theentity references elements in the DOM tree.</p><p>Note that at save time libxml2 enforces the conversion of the +predefinedentities where necessary to prevent well-formedness problems, and +will alsotransparently replace those with chars (i.e. it will not generate +entityreference elements in the DOM tree or call the reference() SAX callback +whenfinding them in the input).</p><p><span style="background-color: #FF0000">WARNING</span>: handling +entitieson top of the libxml2 SAX interface is difficult!!! If you plan to +usenon-predefined entities in your documents, then the learning curve to +handlethen using the SAX API may be long. If you plan to use complex +documents, Istrongly suggest you consider using the DOM interface instead and +let libxmldeal with the complexity rather than trying to do it yourself.</p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html> |